I am aware that if you don't take a sector the remainder of your ticket should get cancelled.

However, there are so many things that can go wrong that I'm not sure if BA actually does this. Imagine that for some reason you weren't properly recorded as making the outbound flight and turn up at the airport for the return only to be told that your ticket had been cancelled. I'm sure we would hear a few cases like this on FT but I don't remember any!

I am planning to put this to the test. I have a non-changeable ticket that I have to throw away as the outbound no longer suits my plans. However I'd still take the return sector if I could. As a result, I booked a return on another airline whose flight leaves 15 minutes after BA. I'll try to check-in for the return BA flight and get on it. If I'm refused travel I'll then take the flight on the other airline.

I'll report back once I've tried to do this.

As anyone had the remainder of the ticket actually cancelled? Answers below please